//
//  Person.m
//  12-gcd常用函数
//
//  Created by J on 16/2/25.
//  Copyright © 2016年 J. All rights reserved.
//

#import "Person.h"

@implementation Person
- (NSArray *)books{
    
//    if (!_books) {
//        _books = @[@"1",@"2"];
//        
//    }
    
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _books = @[@"1",@"2"];

    });
    
    return _books;
    
}
@end
